Oxo malonic acid

Methyl- and 3-phenyl-4-hydroxy-2-oxo-2//-pyrido[2,1 -Z)]oxazinium inner salts were prepared in the reaction of 2-pyridone and 2-substituted malonyl chloride, prepared in situ from 2-substituted malonic acid with PCI5 in CH2CI2 (00JCS(P2)2096). 

It has also been stated that malonic acid, benzaldehyde, and ammonia can react to form tribenzaldiiminemalonic acid which under the action of hydrochloric acid is transformed into 6-oxo-2,4-di-phenyltetrahydro-l,3-oxazine (20). This is the only known representative of the 6-oxotetrahydro-l,3-oxazines. 

The starting material may be produced by reacting 6-amino-2-methylthiopyrimidine with ethoxymethylene malonic acid diethyl ester. The intermediate thus produced is converted by boiling in diphenyl ether to 6-ethoxycarbonyl-2-methylthio-5-oxo-5,B-dihydropyrido-[2,3-d]pyrimidine. That is hydrolyzed by sodium hydroxide to cleave the ethoxy group and then ethylated with diethyl sulfate to give the starting material. 

Dimethyl mesoxolate Propanedioic acid, oxo-, dimethyl ester (9) (3298-40-6) Dimethyl benzalmalonate Malonic add, benzylidene-, dimethyl ester (8) Propanedioic add, (phenylmethylene)-, dimethyl ester (9) (6626-84-2) Dimethyl sulfide Methyl suflide (8) Methane, thiobis- (9) (75-18-3)... 

Table 20 Ring closures to [1,2,4]triazolo[1,5-a]pyrimidines by reaction of 3-amino[1,2,4]triazoles with /3-oxo ketones, esters, nitriles, or malonic acid derivatives...

With diketene, intermediates of type (III) were isolated and subsequently cyclized under basic conditions following step (b). In the case of 3-oxo-carboxylic acid esters or 3-acyl Meldrum s acids, cyclization step (b) immediately follows reaction step (a), if a slight excess of amine is employed (85TH1 87TH1). Note that conversion of (III) to (V) involves the (IH)-enol (Table I cf. 75BSF2731). The relatively low yield in the case of malonic acid ester, as well as the failure of the reaction with the non-enolizable diphenyl phosphinylacetic ester and cyanoacetate, points to the participation of an enol structure of (III). 

Conversion of esters of acylated aminoisobutyryl malonic acids into 3-oxo-A2-pyrrolines [182-183],... 

Esterification of resin-bound alcohols with 3-oxo carboxylic acids (which readily undergo decarboxylation) or with malonic acid is best performed using the corresponding ketenes, which can be generated in situ by thermolysis of dioxinones or other precursors (Entries 6-9, Table 13.12). PEG can also be acetoacetylated with acetyl ketene generated by thermolysis [171]. 

Ouino.xaline di-.Af-oxides are not formed in the reaction of benzofuroxan v/ith malonic acid or malonales however, benzofuroxan reacts smoothly with ethyl cyanoacetate in the presence of a strong base such as l,5-diazabicyclo[4.3.0]non-5-ene (DBN) or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) with the elimination of alcohol to give 3-hydroxyquinoxaline-2-carbonitrile 1,4-dioxide. According to spectroscopic studies, the tautomeric equilibrium is shifted towards l-hydroxy-2-oxo-l,2-dihydroquinoxalin-3-carbonitrile 4-oxide. 

The aliphatic products from high ozone exposure are typically much less reactive than their precursors, but their further oxidation cannot be totally disregarded. From studies of the ozonation of malonic acid (Dobinson 1959), saccharides (Godsay and Pearce 1984, Matsumoto et al. 1984b, Bonnet et al. 1989), and erythronic and threonic acids (Tsutsumi et al. 1990), it is clear that aliphatic oxy, oxo, and carboxylic compounds all undergo further, usually slow, degradation by ozone. 

In another case, the bidentate malonic acid is replaced with two trans-wattr molecules, leaving the coordination environment the same, but causing the irans-oxo ligands to rotate 90°. ... 

The C-C-C fragments in this method are provided by 2,4,6-trichlorophenyl esters of substituted malonic acids, which are condensed with methyl 4-amino-6-oxo-l-phenyl-l,6-dihydropy-ridazine-3-carboxylate by heating at 240 °C to give products 2. The less reactive dialkyl mal-onates yield decomposition products only.70... 

Amino-2,4-dioxo-l,2,3,4-tetrahydropyrimidine-5-carbaldehydes have been treated with activated methylene compounds such as malonic acid derivatives, fi-oxo esters, or -nitriles. The Knoevenagel condensation between the aldehyde function and the activated methylene group to build up the side chain is followed by cyclization. 

Like malonic acids, acetoacetic acid and analogous / -oxo acids are more readily decarboxylated as undissociated acids than as their anions. The rate equation for the two types of acid is the same ... 

The second target, 4-oxo-4H-l-benzopyran-3-carboxylic acids (3) were obtained by Jones oxidation of or hydrolysis of the 3-carbonitrile derivatives ( ) described below (14). The third target, 3-(4-oxo-4H-1-benzopyran-3)acrylic acids (4) were synthesized generally by the Knoevenagel reaction of 3-carboxaldehydes (2) with malonic acid ( 1 ). In the meantime, it was found that the 3-carboxaldehydes ( ), which were able to function as P-dialdehyde compounds, were attacked by amide groups in some cases, to give 2(IH)-pyridone derivatives after condensation with malonic acid derivatives. Thus, condensation of 2 with malonodiamide in pyridine gave initially acrylamide derivatives which were converted into 3-carbamoyl-5-(2-hydroxybenzoyl)-2(IH)-pyridones ( ) (24) ... 

A less familiar ring system, but one that was part of a molecule selected for advanced testing, was the 5-methyl-6-oxo-4-(trifluoromethyl)-l-(6H)-pyridazinyl ring system of flufenpyr-ethyl (43). The pyridazinyl heterocycle can be prepared from the reaction of 4-chloro-2-fluoro-5-hydroxyphenyl hydrazine (48) and 1,1-dibromo-3,3,3-trifluoroacetone (49) to give the corresponding hydrazone 50, which when reacted with methyl malonic acid (51), in the presence of a base, provides the intermediate 52. Acid-catalyzed ring closure of 52, followed by 0-alkylation of 53 with ethyl chloroacetate, results in the synthesis of flufenpyr-ethyl (43) [73] (Scheme 3.2). 

Vecchio and his co-workers (8 2,63,64 synthesize a great variety of isoxazole derivatives. The substrates used were cyanoketones acetoacetates (46,47) jS-oxo-esters (, 64 malonic acid amides ( ). 

In a 50-mL round-bottomed flask were placed 0.265 g 4-aminoindole (2.0 mmol) and 0.405 mL diethyl ethoxymethylenemalonate (2.0 mmol, d = 1.07) the mixture was heated at 130°C for 3 h. Any unreacted diethyl ethoxymethylenemalonate was removed under vacuum, leaving 0.50 g 2-[( 1//-indol-4-ylamino)methylene]malonic acid diethyl ester as a brown solid, in a yield of 83%, m.p., 122°C (ethanol). Then 0.50 g of the solid diester (1.7 mmol) was added to 50 mL boiling diphenyl ether in portions after 20 min of refluxing, the precipitate formed by cooling was collected by flltration, washed many times with diethyl ether, and recrystallized from ethanol, yielding 0.360 g ethyl 4-oxo-4,7-dihydro-lH-pyrrolo[2,3-/z]quinolin-3-carboxylate, in ayieldof83%, m.p.280°C (dec.), Rf = 0.45 (EtOAc/MeOH, 8 2). 

Oxo-octadecanoic acids dideuterated in y-position on the carboxyl side were prepared from 4,4-dideuterated co -unsaturated acids as shown in Figure 6, by acylation of substituted malonic acid, functional group manipulation the last step was the oxidation of the terminal methylene unit to carboxylic acid. 

Although azide reagents have been utilized in a number of chemical transformations, to date PS-TsA has only been utilized for the direct transfer of a diazo function to methylene groups flanked by either two carbonyls (eq 2), a carbonyl and an aryl sulfonyl (eq 3), or the methylene of lO/ anthracen-9-one. Diazodicarbonyl compounds such as 5-diazo-2,2-dimethyl-[l,3]dioxane-4,6-dione, 2-diazo-3-oxo-butyric acid ethyl ester, lO-diazo-lO/ anthracen-9-one, 2-diazo malonic acid diethyl ester, and 2-diazo-3-oxo-butyric acid ter/-butyl ester, as well as... 

Thermal degradation prior to ionization can cause decarbonylation or decarboxylation of the analyte. Decarbonylation, is observed for a-ketocarboxylic acids and a-ketocarboxylic acid esters, while decarboxylation is typical for p-oxo-carboxylic acids such as malonic acid and its derivatives and di-, tri-, or polycar-boxylic acids. 

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